Funds are requested for an intermediate field (4.7T) nmr spectrometer for observations of proton, carbon and fluorine nuclei. Availability of this instrument will have a significant, favorable impact on the research programs of NIH grant holders in the Department involved in (1) mechanistic studies of hydrocarbon carcinogenicity, detoxification of xenobiotic and naturally occuring amines and organic sulfides, and the chemistry of pterino flavins; (2) structural studies of fluorine-containing proteins, preparation of enzyme inhibitors and study of proteins in microheterogeneous environments; (3) development of new synthetic chemistry for the construction of antibiotic and antitumor agents; and (4) study of neurochemical mechanisms. Applications of the requested instrumentation include its use in structure elucidation, studies of rate phenomena, equilibration of conformational forms and definition of molecular motions by means of nuclear relaxation data.